Although the following description refers primarily to bicycles, it will be readily appreciated that other means of propulsion may equally benefit from employment of the inventive principles. Consequently any reference to a bicycle is meant to encompass any similar mode of transport whereby suitable application, modification or adaptation of the invention can be applied.
It has long been recognised that the aerodynamics of a bicycle are strongly effected by the aerodynamic performance of the wheels in particular. This is particularly true for racing, but is equally applicable to leisure pursuits involving bicycles. In other words the better aerodynamic performance of the wheels of a bicycle, the easier it is to ride. A cyclist has in any event to pedal to propel himself forward and any substantial drag caused by the bicycle, and the wheels in particular, lessens the speed obtainable by the cyclist for the effort expended.
It is known for racing bicycles in particular to have at least the rear wheel made from a lightweight material in the form of a disc. The aerodynamics of such a disc wheel are such that the drag on the bicycle is lessened when compared to the conventionally spoked wheel. These types of disc wheels are usually made from a composite material and although extremely light in weight, they are relatively stiff and easily damaged and as such are suited for use on a racing track where the surface is extremely even. These types of wheels are unsuitable for use on uneven surfaces as they are easily damaged if they strike any protrusion such as can be found on roads or similar surfaces.
In addition, these types of disc wheels are most suitable when used on indoor tracks because when they are used outdoors problems arise with regard to crosswinds which tend to cause aerodynamic drag. This drag removes the advantages gained in the aerodynamic performance of the wheels due to their disc nature,
Further to the above, there are known wheels which have been designed to overcome the above mentioned disadvantage by providing a lightweight spoked wheel whereby the at least three spokes and rim are made from composite materials of a similar nature to the composite discs. The rim extends inwardly towards the axle a short distance for strength and to provide an aerodynamic advantage over a conventionally spoked bicycle wheel. These wheels are supposed to absorb road shock and the like and reduce fatigue of the composite material, while reducing the drag caused by cross winds to the above described disc wheels while also providing improvements in aerodynamic performance over the conventionally spoked bicycle wheel.
However, it has been found that these wheels are also easily damaged if used on roads or the like and especially if the road conditions are rough. These wheels are not easily able to be repaired. This means that if the wheel is only slightly damaged, the wheel will have to be discarded as it is unable to perform as it is supposed. This is a relatively expensive wheel to purchase and therefore as they appear to be easily damaged, they have not been universally adopted.
Another type of bicycle wheel that is known and which has been developed to overcome the disadvantages associated with the aerodynamics of conventionally spoked bicycle wheels is a wheel that includes an annulus shaped rim which extends substantially inwardly from the outer edge and a number of metal spokes which extend between the axle and the annulus shaped rim in the same manner as a conventionally spoked bicycle wheel, The metal spokes are embedded into the annulus shaped rim which is made from plastics materials such as carbon fiber resins.
In a similar manner to the previously described wheels, this wheel has the disadvantage that if the wheel is only slightly damaged it will have to be discarded as it is unable to be repaired satisfactorily for its intended use.
Therefore it would be advantageous to provide a wheel and/or wheel apparatus which enables the cyclist to have improved aerodynamic performance as compared to a conventionally spoked bicycle wheel as well as being a wheel and/or wheel apparatus which is easily repaired when damaged. Such an apparatus could be able to be adapted to be applied to a conventionally spoked wheel such that the conventionally spoked bicycle wheel is improved aerodynamically without the need to use the costly wheels as described above.